According to a report from analyst Ming-Chi Kuo of KGI Securities, the release of the 5.5-inch iPhone 6 model could be pushed back to 2015.

The main concern seems to be the touchscreen edges which are not reliable for the larger screen.

This problem is present on both iPhone 6 versions, but it would be easier to solve on the smaller model.

Another production concern is the color inequality that affects the metal shell.

“Production bottlenecks on 4.7-inch iPhone 6 center on the yield rate of in-cell touch panel and metal casing,” Kuo said. “As in-cell touch panel becomes larger in size, the edge of the panel may become insensitive to touch. Meanwhile, under new manufacturing process for the iPhone 6 metal casing, color unevenness is an issue.”

The analyst assumes that the phablet iPhone will be available after October at the earliest and if so, likely in limited edition.

Analyst Ming-Chi Kuo has always been very reliable in his predictions about Apple products in the past.